diff --git a/hw/ne2000-isa.c b/hw/ne2000-isa.c
index e41dbba..756ed5c 100644
--- a/hw/ne2000-isa.c
+++ b/hw/ne2000-isa.c
@@ -27,6 +27,7 @@
 #include "qdev.h"
 #include "net.h"
 #include "ne2000.h"
+#include "exec-memory.h"
 
 typedef struct ISANE2000State {
     ISADevice dev;
@@ -66,19 +67,11 @@ static int isa_ne2000_initfn(ISADevice *dev)
     ISANE2000State *isa = DO_UPCAST(ISANE2000State, dev, dev);
     NE2000State *s = &isa->ne2000;
 
-    register_ioport_write(isa->iobase, 16, 1, ne2000_ioport_write, s);
-    register_ioport_read(isa->iobase, 16, 1, ne2000_ioport_read, s);
+    ne2000_setup_io(s, 0x20);
     isa_init_ioport_range(dev, isa->iobase, 16);
-
-    register_ioport_write(isa->iobase + 0x10, 1, 1, ne2000_asic_ioport_write, s);
-    register_ioport_read(isa->iobase + 0x10, 1, 1, ne2000_asic_ioport_read, s);
-    register_ioport_write(isa->iobase + 0x10, 2, 2, ne2000_asic_ioport_write, s);
-    register_ioport_read(isa->iobase + 0x10, 2, 2, ne2000_asic_ioport_read, s);
     isa_init_ioport_range(dev, isa->iobase + 0x10, 2);
-
-    register_ioport_write(isa->iobase + 0x1f, 1, 1, ne2000_reset_ioport_write, s);
-    register_ioport_read(isa->iobase + 0x1f, 1, 1, ne2000_reset_ioport_read, s);
     isa_init_ioport(dev, isa->iobase + 0x1f);
+    memory_region_add_subregion(get_system_io(), isa->iobase, &s->io);
 
     isa_init_irq(dev, &s->irq, isa->isairq);
 
diff --git a/hw/ne2000.c b/hw/ne2000.c
index f8acaae..5b76acf 100644
--- a/hw/ne2000.c
+++ b/hw/ne2000.c
@@ -297,7 +297,7 @@ ssize_t ne2000_receive(VLANClientState *nc, const uint8_t *buf, size_t size_)
     return size_;
 }
 
-void ne2000_ioport_write(void *opaque, uint32_t addr, uint32_t val)
+static void ne2000_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 {
     NE2000State *s = opaque;
     int offset, page, index;
@@ -394,7 +394,7 @@ void ne2000_ioport_write(void *opaque, uint32_t addr, uint32_t val)
     }
 }
 
-uint32_t ne2000_ioport_read(void *opaque, uint32_t addr)
+static uint32_t ne2000_ioport_read(void *opaque, uint32_t addr)
 {
     NE2000State *s = opaque;
     int offset, page, ret;
@@ -544,7 +544,7 @@ static inline void ne2000_dma_update(NE2000State *s, int len)
     }
 }
 
-void ne2000_asic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
+static void ne2000_asic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 {
     NE2000State *s = opaque;
 
@@ -564,7 +564,7 @@ void ne2000_asic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
     }
 }
 
-uint32_t ne2000_asic_ioport_read(void *opaque, uint32_t addr)
+static uint32_t ne2000_asic_ioport_read(void *opaque, uint32_t addr)
 {
     NE2000State *s = opaque;
     int ret;
@@ -612,12 +612,12 @@ static uint32_t ne2000_asic_ioport_readl(void *opaque, uint32_t addr)
     return ret;
 }
 
-void ne2000_reset_ioport_write(void *opaque, uint32_t addr, uint32_t val)
+static void ne2000_reset_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 {
     /* nothing to do (end of reset pulse) */
 }
 
-uint32_t ne2000_reset_ioport_read(void *opaque, uint32_t addr)
+static uint32_t ne2000_reset_ioport_read(void *opaque, uint32_t addr)
 {
     NE2000State *s = opaque;
     ne2000_reset(s);
@@ -676,27 +676,55 @@ static const VMStateDescription vmstate_pci_ne2000 = {
     }
 };
 
-/***********************************************************/
-/* PCI NE2000 definitions */
+static uint64_t ne2000_read(void *opaque, target_phys_addr_t addr,
+                            unsigned size)
+{
+    NE2000State *s = opaque;
 
-static void ne2000_map(PCIDevice *pci_dev, int region_num,
-                       pcibus_t addr, pcibus_t size, int type)
+    if (addr < 0x10 && size == 1) {
+        return ne2000_ioport_read(s, addr);
+    } else if (addr == 0x10) {
+        if (size <= 2) {
+            return ne2000_asic_ioport_read(s, addr);
+        } else {
+            return ne2000_asic_ioport_readl(s, addr);
+        }
+    } else if (addr == 0x1f && size == 1) {
+        return ne2000_reset_ioport_read(s, addr);
+    }
+    return ((uint64_t)1 << (size * 8)) - 1;
+}
+
+static void ne2000_write(void *opaque, target_phys_addr_t addr,
+                         uint64_t data, unsigned size)
 {
-    PCINE2000State *d = DO_UPCAST(PCINE2000State, dev, pci_dev);
-    NE2000State *s = &d->ne2000;
+    NE2000State *s = opaque;
+
+    if (addr < 0x10 && size == 1) {
+        return ne2000_ioport_write(s, addr, data);
+    } else if (addr == 0x10) {
+        if (size <= 2) {
+            return ne2000_asic_ioport_write(s, addr, data);
+        } else {
+            return ne2000_asic_ioport_writel(s, addr, data);
+        }
+    } else if (addr == 0x1f && size == 1) {
+        return ne2000_reset_ioport_write(s, addr, data);
+    }
+}
 
-    register_ioport_write(addr, 16, 1, ne2000_ioport_write, s);
-    register_ioport_read(addr, 16, 1, ne2000_ioport_read, s);
+static const MemoryRegionOps ne2000_ops = {
+    .read = ne2000_read,
+    .write = ne2000_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
 
-    register_ioport_write(addr + 0x10, 1, 1, ne2000_asic_ioport_write, s);
-    register_ioport_read(addr + 0x10, 1, 1, ne2000_asic_ioport_read, s);
-    register_ioport_write(addr + 0x10, 2, 2, ne2000_asic_ioport_write, s);
-    register_ioport_read(addr + 0x10, 2, 2, ne2000_asic_ioport_read, s);
-    register_ioport_write(addr + 0x10, 4, 4, ne2000_asic_ioport_writel, s);
-    register_ioport_read(addr + 0x10, 4, 4, ne2000_asic_ioport_readl, s);
+/***********************************************************/
+/* PCI NE2000 definitions */
 
-    register_ioport_write(addr + 0x1f, 1, 1, ne2000_reset_ioport_write, s);
-    register_ioport_read(addr + 0x1f, 1, 1, ne2000_reset_ioport_read, s);
+void ne2000_setup_io(NE2000State *s, unsigned size)
+{
+    memory_region_init_io(&s->io, &ne2000_ops, s, "ne2000", size);
 }
 
 static void ne2000_cleanup(VLANClientState *nc)
@@ -724,9 +752,9 @@ static int pci_ne2000_init(PCIDevice *pci_dev)
     /* TODO: RST# value should be 0. PCI spec 6.2.4 */
     pci_conf[PCI_INTERRUPT_PIN] = 1; // interrupt pin 0
 
-    pci_register_bar(&d->dev, 0, 0x100,
-                           PCI_BASE_ADDRESS_SPACE_IO, ne2000_map);
     s = &d->ne2000;
+    ne2000_setup_io(s, 0x100);
+    pci_register_bar_region(&d->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &s->io);
     s->irq = d->dev.irq[0];
 
     qemu_macaddr_default_if_unset(&s->c.macaddr);
@@ -754,6 +782,7 @@ static int pci_ne2000_exit(PCIDevice *pci_dev)
     PCINE2000State *d = DO_UPCAST(PCINE2000State, dev, pci_dev);
     NE2000State *s = &d->ne2000;
 
+    memory_region_destroy(&s->io);
     qemu_del_vlan_client(&s->nic->nc);
     return 0;
 }
diff --git a/hw/ne2000.h b/hw/ne2000.h
index 54fdfca..5fee052 100644
--- a/hw/ne2000.h
+++ b/hw/ne2000.h
@@ -4,6 +4,7 @@
 #define NE2000_MEM_SIZE     NE2000_PMEM_END
 
 typedef struct NE2000State {
+    MemoryRegion io;
     uint8_t cmd;
     uint32_t start;
     uint32_t stop;
@@ -27,12 +28,7 @@ typedef struct NE2000State {
     uint8_t mem[NE2000_MEM_SIZE];
 } NE2000State;
 
-void ne2000_ioport_write(void *opaque, uint32_t addr, uint32_t val);
-uint32_t ne2000_ioport_read(void *opaque, uint32_t addr);
-void ne2000_asic_ioport_write(void *opaque, uint32_t addr, uint32_t val);
-uint32_t ne2000_asic_ioport_read(void *opaque, uint32_t addr);
-void ne2000_reset_ioport_write(void *opaque, uint32_t addr, uint32_t val);
-uint32_t ne2000_reset_ioport_read(void *opaque, uint32_t addr);
+void ne2000_setup_io(NE2000State *s, unsigned size);
 extern const VMStateDescription vmstate_ne2000;
 void ne2000_reset(NE2000State *s);
 int ne2000_can_receive(VLANClientState *vc);
